You've gotten some great advice. Another thing I would offer is that babies go through growth spurts. it's best to try not to obsess over the numbers!!

I went through a period like this around 6 weeks.. it was awful because by about 6 pm I felt like I had nothing left to offer. And DH LOVES to nurse, which just means that she would get frustrated when nothing came out..

nurse and pump, try some of the herbal suggestions, and your supply WILL go back up. A tiny bit of weight loss is really nothing to worry about. If it gets out of hand tho and the pedi pushes you to supplement with a bottle, remember that will HURT your supply! Instead look into the supplemental nusing system, where your lo receives formula while suckling.

Hang in there momma!! Those first three months are toughies, but you can do it!

ETA: I wouldn't worry about the lack of poopies as long as your LO is getting his wet diapers in! I've read that breast milk is just that perfect for babies that some babies don't end up making a lot of solid waste from it!!